Various stabilizers are known in the art. One type of stabilizer is represented by the device of U.S. Pat. No. 4,982,719 wherein a single mass in the form of a single, tightly-fitting piston is restrained within a hydraulic-fluid-containing-cylinder by conical springs at each end of the piston. A central passage through the piston, and O-rings about the periphery of the piston, causes hydraulic fluid only to flow within the central passage. Radial holes extend from the outer periphery of the piston into the central passage of the piston. Though it is contended that the expense and complexity of producing the radial holes facilitates lubrication and smooth movement of the piston, it is expected that a piston fitting so tightly as to have no fluid flow at its periphery will encounter uneven wall friction and thus inconsistent performance. Wall friction will cause wear of the O-rings and result in changes in the frictional response of the piston. It is also expected that for the piston to be able to move without fluid flow at its periphery, the inside of the cylinder and the piston must have a very accurate fit. Such a device, at best, has the same response in both directions, requires high precision and effort in its manufacture, is expected to have inconsistent performance, and to have a limited life.
Another class of stabilizer is represented by the device in U.S. Pat. No. 5,016,602 wherein a cylinder is partially filled with granular solids that can move back and forth to dissipate some of the energy of an applied impulse. It is also known to use a viscus fluid (such as mercury) within a cylinder to effect a similar result. Such devices tend to have good service life but are limited in adjustment.
Known devices are generally cylindrical or elongated (and thus tend to have similar external appearances) and are expected inherently to have essentially the same response in both directions. Accordingly, an object of the present invention is a stabilizer capable of damping a mechanical impulse in one direction with a different amount of mass and damping than in the opposite direction.
A more particular object of the present invention is a stabilizer that is relatively inexpensive and easy to construct, having few parts that are either simple to make or are stock items. Additionally, an object is ease of varying the response merely by changing the density or length of a part or the size of a hole. It is also an object to provide optional means for the operation of the present invention to take place quietly. Lastly, it is an object to have a device having consistent performance over a long service life.